The head of a state crime lab office was fired Monday after investigators found that staff withheld exculpatory evidence from defense lawyers in thousands of drunken-driving cases since 2011, a disclosure that could threaten many convictions.

In a report released Monday, state public safety officials concluded that the Office of Alcohol Testing routinely withheld documents from defense lawyers in a lawsuit challenging the reliability of breathalyzer test results due to an “unwritten policy not to turn these documents over to any requester.”

The documents included evidence that breath testing devices had failed to properly calibrate during the office’s certification process, the report found.

“We conclude that OAT leadership made serious errors of judgment in its responses to court-ordered discovery, errors which were enabled by a longstanding and insular institutional culture that was reflexively guarded . . . and which was inattentive to the legal obligations borne by those whose work facilitates criminal prosecutions,” the report found.

The most important word in the above excerpt is “culture.” The drug tests scandal was blamed on a single analyst, Annie Dookhan. But these sorts of things rarely happen in isolation. Now we have an entire “office” within the crime lab accused of not turning over exculpatory evidence. At some point, we need to start asking pointed questions. Among them: Why would crime-lab analysts feel pressure to fake incriminating test results and to hide exculpatory results? Are they feeling pressure from police or prosecutors? We already know that, incredibly, some crime labs only get funding when their analysts produce results that help win convictions. Is that what’s happening here? There are numerous public and private grants and awards tied to driving-under-the-influence enforcement, both for police departments as a whole and for individual officers. Was that a factor here?

Crime-lab analysts should be neutral. Their job performance should be evaluated based on their accuracy. Clearly, something is making at least some of these analysts think there’s a “right” and a “wrong” answer when conducting these tests. Perhaps it’s right there in the name: the Massachusetts State Police Crime Laboratory. A forensic analyst shouldn’t be considered on the same side or team as the police. Hosting these labs under the auspices of police or district attorney’s offices is a big part of the problem.

If the lab was indeed withholding exculpatory test results, that almost certainly means some people were wrongly convicted of DUI. In Massachusetts, a first-time drunk-driving conviction can bring a one-year suspension of your driver’s license, possible probation and a mandatory 16-week alcohol awareness class (that you’re required to pay for), and thousands of dollars in court costs, attorney’s fees and fines. The conviction remains on your record permanently. If you had a child in the car at the time, you’re looking at 90 days to two years in prison and a one-year license suspension. And none of this accounts for the harm done to your career and reputation. A DUI conviction can be used against you in divorce and child custody cases. It can be devastating if you’re on parole or probation.

Given the stakes, and what we now know about the crime lab, if you find yourself pulled over on suspicion of DUI, you might be tempted to refuse to take a breath test. Generally speaking, unless you were driving really recklessly, or there are other signs of obvious intoxication, it takes a positive breath test to get probable cause to arrest you and subject you to a blood test. But refusing the test won’t help. Massachusetts is also one of the majority of states that mandates an automatic license suspension if you refuse to take a breath test. (Unless, of course, you’re a police officer, and have been extended “professional courtesy” by your fellow officer.)

These scandals will continue until states and cities create systems that recognize and compensate for cognitive bias, and in which the incentive structure rewards accuracy above all else.

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Radley Balko writes and edits The Watch, a reported blog covering civil liberties and the criminal-justice system. Previously, he was an investigative reporter for the Huffington Post and a writer and editor for Reason magazine. His most recent book is "The Cadaver King and the Country Dentist: A True Story of Injustice in the American South."